Anesthesiology
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Comparative Study Clinical Trial
Increase of oxygen consumption during a progressive decrease of ventilatory support is lower in patients failing the trial in comparison with those who succeed.
The aim of this study was to test the hypothesis that, during weaning from mechanical ventilation, when the pressure support level is reduced, oxygen consumption increases more in patients unable to sustain the decrease in ventilatory assistance (weaning failure). ⋯ Patients failing a decremental pressure support trial, in comparison with those who succeed, had an higher baseline oxygen consumption and were not able to increase their oxygen consumption in response to an increased demand.
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Comparative Study
Lumbar intrathecal administration of the quaternary lidocaine derivative, QX-314, produces irritation and death in mice.
We recently found that peripheral administration of the quaternary lidocaine derivative, QX-314, produces long-lasting sensory and motor blockade in animals. The goal of this study was to test whether intrathecal QX-314 has similar properties. ⋯ Lumbar intrathecal QX-314 concentration-dependently produced irritation and death in mice, at lower concentrations than those associated with robust motor blockade. Although QX-314 did produce long-lasting neural blockade, these findings indicate that QX-314 is unlikely to be a suitable candidate for spinal anesthesia in humans.
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Comparative Study
Dexmedetomidine in the care of critically ill patients from 2001 to 2007: an observational cohort study.
Dexmedetomidine is a novel sedative agent that causes anxiolysis without respiratory depression in critically ill patients. We sought to examine patient and hospital variation in dexmedetomidine use and adoption patterns of dexmedetomidine over time. ⋯ Use of dexmedetomidine in critically ill patients has increased over time, primarily as a result of an increase in use among cardiac surgery patients. A substantial portion of dexmedetomidine was administered outside of the regulatory approval guidelines at the time.
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Comparative Study
Enhancement of GABAergic tonic currents by midazolam and noradrenaline in rat substantia gelatinosa neurons in vitro.
Substantia gelatinosa of the spinal dorsal horn is crucial for transmission and modification of noxious stimuli. Previous studies have demonstrated that intrathecal midazolam, a benzodiazepine agonist, enhanced perioperative analgesia. Not only synaptic but also extrasynaptic inhibitory currents contribute to modification of noxious stimuli. Thus, the effects of midazolam on extrasynaptic gamma-aminobutyric acid (GABA) type A receptors in substantia gelatinosa neurons and interaction with noradrenaline, a transmitter of the descending inhibitory systems, were investigated. ⋯ Midazolam had much larger effects on extrasynaptic GABA type A receptors than the synaptic receptors, suggesting a role of the enhancement of GABAergic extrasynaptic currents in the midazolam-induced analgesia. Because noradrenaline is shown to increase extrasynaptic GABA concentration, simultaneous administration of noradrenaline and midazolam may enhance the increased GABA action by midazolam, thereby resulting in an increase in tonic extrasynaptic currents.